Method and apparatus for preventing soot fallout aboard ship



T. T. LUNDE Aug. 9, 1966 METHOD AND APPARATUS FOR PREVENTING SOOT FALLOUT ABOARD SHIP Filed Jan. 27, 1965 INVENTOR THOMAS 7. LUNDE United States Patent 3,265,031 METHOD AND APPARATUS FOR PREVENTING 500T FALLOUT ABOARD SHIP Thomas T. Lands, 233 Cerrantes Blvd,

' San Francisco, Calif. Filed Jan. 27, 1965, Ser. No. 428,353 2 Claims. (Cl. 114-487) This invention relates to a method and apparatus for preventing soot fallout aboard ships.

It is common knowledge that soot fallout aboard ship is a particularly annoying problem and, in the case of large passenger ships, may sometimes become so aggravated as to effectively deny use of certain deck areas by the passengers. With some ships it is impossible to discharge the smoke column from the ships smoke stack with enough upward velocity to prevent a fallout of soot particles under even the most favorable conditions. In such cases aesthetic considerations usually preclude increasing the height of the stack so that the problem must be solved by other than the obvious expedient.

In the past, various devices including fans and baffles 'have been tried in attempts to overcome the problem. In addition, the smoke stack has been formed in various shapes and sizes to create an updraft around the smoke column. So far as we are aware, however, these prior attempts to solve the problem of soot fallout have not been completely satisfactory, either because of lacking in effectiveness or because of costs to install and operate. Moreover, many devices which have been used are effective only under certain favorable wind conditions, and because of the infinite variety of conditions that may be encountered during a ships voyage, they may be impractical.

In brief, the present invention contemplates a method whereby an annular column of air is formed around the smoke column as it is emitted from the stack. Although this feature alone is not novel, it is more particularly contemplated that the annular air column be formed with a variable thickness in cross section, the greatest thickness of the column being located on the side of the smoke stack nearest to the greatest shipboard area, or that area of the ship to be protected. The column of air is then moved upwardly in a direction parallel to the smoke column to create a barrier of moving air. It has been found that the air column should be moved at a rate at least equal to the velocity of the smoke column to prevent undesirable drag, air turbulence and an intermixing of the air and smoke columns.

This invention further contemplates positioning the ship relative to prevailing air currents at periodic intervals as to carry the smoke column crosswise of the ship. At this time the smoke stack is vibrated vigorously to loosen soot accumulations within the stack.

Under normal operating conditions the annular column of air, as above described, will function much the same as an extended chimney, especial-1y on that side of the smoke stack nearest to the protected area. Thus, when prevailing air currents, attributable either to weather conditions or to the speed of the ship and its direction, or both, tend to carry soot over the protected area, the height of the smoke column will be much greater than would otherwise result if the annular column of air were not used. In the event that air currents which effect the smoke column are nil, the smoke column will nevertheless be maintained and, in fact, rise to a higher distance than where no annular air column is used. Therefore, there will be much less soot fallout over the protected area.

The importance of vibrating the smoke stack at periodic intervals is to guard against sudden discharge of large carbon deposits. Such deposits usually form Within the stack, and unless deliberately removed, they may be released and expelled from the stack at an unfortunate moment. Moreover, the size of some carbon deposits which are formed may cause them to gravitate onto the protected area of a ship despite the use of the annular column as described. It has been found, however, that a periodic controlled discharge of the large soot particles may be produced by vibrating the stack, and this may be conveniently done while the prevailing air currents carry the smoke column cross-wise of the ship. If need be, the ship may be positioned relative to the Wind currents during the brief period required for this operation.

One object of this invention, therefore, is to provide a simple method for preventing soot fallout aboard ship.

Another object is to provide apparatus for carrying out the method which can be inexpensively incorporated into new ship construction or into existing smoke stack arrangements.

Other objects of this invention will, of course, become apparent in view of the following detailed description and the accompanying drawings.

In the drawings forming a part of this application and in which like parts are identified by like reference numerals throughout,

FIG. 1 is a side elevation of .a ships smoke stack constructed in accordance with the teachings of the invention;

FIG. 2 is an enlarged side elevation and vertical section of the smoke stack construction shown in FIG. 1;

FIG. 3 is a top view of the smoke stack as viewed on lines 3-3 of FIG. 2; and

FIG. 4 is a detail of a vibrator mounted on the outer surface of the inner smoke stack, said detail being a partial section taken on lines 4-4 of FIG. 1.

Referring to FIG. 1, there is illustrated the upper stack 10 of a ship or vessel (not otherwise shown). An inner smoke stack 11 extends through the upper stack in conventional fashion for conducting soot particles from the furnaces of the ship and discharging the particles into the air as a smoke column 12.

The present invention more particularly relates to the use of an annulus 13 disposed around the upper end of inner stack 11 for creating an annular column of air about smoke column 12. With reference to FIGS. 2 and 3, both the upper opening of inner stack 11 and the upper opening of annulus 13 are circular, the centers of the openings being displaced from each other in a direction longitudinal of the ship with the inner surface of annulus 13 and the outer surface of inner stack 11 defining an annular area 14 of varying thickness. More importantly, the opening of annulus 13 is positioned relative to the opening of inner stack 11 such that the thickest section 1401 of annular space 14 is provided on that side of the smoke column or stack nearest to an area on the ship that is to be especially protected against soot fallout. For example, annulus 13 is oriented relative to inner stack 11 as to provide fallout protection for an area on the left of stack 10. Such an arrangement is of particular importance where the ships bow is on the right side of the stack, since the smoke column 12 would, then, trial out over the area to be protected during forward movement of the ship.

In a more or less conventional manner, waste air is delivered into a space or plenum chamber 15 defined by the outer stack 10. This air is then moved under pressure through the annulus 16 as shown in FIG. 2, creating an annular column of air that acts as a barrier between smoke column 12 and the atmosphere. The amount of air delivered into chamber 15 is best regulated to suit the speed of the ship and the velocity of the smoke column. In particular, a sufiicient amount of air should be available to create an annular air column that moves at a rate at least as great as the movement of smoke column 12.

As indicated above, it is common practice to discharge waste or contaminated air, such as that withdrawn from cooking spaces, water closets, etc., from the plenum of an outer stack. The amount of such waste air may be sufficient to create the necessary annular air column contemplated by this invention, however, inasmuch as the waste gases are commonly discharged through lateral port openings formed in the side of the outer stack, certain of these openings may be sealed oil to attain the desired amount of air flow through annulus 13. If necessary, of course, additional amounts of fresh air may be introduced into plenum by means of supplemental blowers, but normal operations on many ships will provide more than enough waste air to produce the desired flow discharge. In some instances lateral openings 17 may be necessary to control the back pressure of the plenum and get rid of excess amounts of waste gas or contaminated air. Adjustable port covers or doors maybe used with such auxiliary openings to permit an adjustment in the amount of air that escapes therethrough from plenum 15. In this way both the pressure within plenum 15 and the amount of air expelled through annulus 13 may be modified to produce optimum results.

It has been found that the annular air column should be moved at a velocity at least as great as the velocity of the smoke column at full power. Of course, the height to which the smoke column should be protected by an annular air barrier depends largely on the size of the ship and its speed. Nevertheless, favorable results have been obtained where the velocity of the smoke and annular columns were barely in excess of the ships speed, and these results were obtained using only conventional ship construction without the aid of supplemental blowers. Thus, it has been fully demonstrated that the invention can be applied to existing ships using the available waste air and gases.

In operation, the annular column of air produced by annulus 13 prevents fallout of soot particles from smoke column 12 until such time that the energy of the annular column has been dissipated or absorbed by friction and turbulence with air particles of the atmosphere. Since plenum chamber 15 is held under a static pressure, the velocity of the annular column is essentially the same all around the smoke column 12, but the volume of air emitted through space 14 is greatest in the area indicated by reference number 14a. Moreover, since the kinetic energy of the air stream is a function of its volume, the portion of the annular air column on the left side of stack 11, as shown, will provide a more effective barrier and be impelled to a greater height than that portion of the air column on the opposite side of the stack.

Although the use of annular columns of air as above described will normally prevent soot fallout from the ordinary smoke column, it is sometimes difficult to prevent fallouts of extremely large particles of soot, which are formed by the buildup of carbon on the inside surface of stack 11. However, it has been found that the prescribed method and apparatus for preventing fallout may be augmented by the use of one or more electric vibrators 18 mounted to the outer surface of the inner stack 11. Such vibrators are periodically activated to loosen carbon deposits within the stack, and this operation is carried out only while prevailing air currents tend to carry the smoke column crosswise of the ship. Thus, the wind is used as an assist to carry the heavier particles to one side of the ship. If necessary, the ship is first turned or positioned to get a beam wind, and while so positioned the vibrators are operated for the minute or so required to clear accumulations from the stacks.

Although a preferred embodiment of this invention has been illustrated and described, various modifications and changes may be made without departing from the spirit of the invention or the scope of the attached claims, and each of such changes is contemplated.

What I claim is:

1. Apparatus for preventing soot fallout onto that portion of a ship which lies to the rear of its smoke stack from the smoke column emitted from said stack comprising, an annulus positioned adjacent the upper end of said stack and defining an annular orifice surrounding the same, means to supply air under pressure to said annular orifice, said annulus being oriented with respect to said stack to provide an annular orifice having an area of greater width to the rear of said stack so that the volume of air to the rear of said stack is greater than the volume of air forward of said stack whereby the portion of the air column established to the rear of said stack will be impelled to a greater height than that portion of the air column on the opposite side of said stack to protect said rear of said ship from soot fallout.

2. The apparatus of claim 1 and further comprising means for vibrating the inner surface of the smoke stack to loosen accumulations of soot thereon.

References (Iited by the Examiner UNITED STATES PATENTS 2,351,163 6/1944 Thomas -84 X FOREIGN PATENTS 503,420 6/ 1951 Belgium.

OTHER REFERENCES Stack Design to Avoid Smoke Nuisance-paper presented at the October 1951 meeting of the New England Section of the Society of Naval Architects and Marine Engineers by H. G. Acker. Bethlehelm Steel Co., Quincy 69, Mass.

MILTON BUCHLER, Primary Examiner.

ANDREW H. FARRELL, Examiner. 

1. APPARATUS FOR PREVENTING SOOT FALLOUT ONTO THAT PORTION OF A SHIP WHICH LIES TO THE REAR OF ITS SMOKE STACK FROM THE SMOKE COLUMN EMITTED FROM SAID STACK COMPRISING, AN ANNULUS POSITIONED ADJACENT THE UPPER END OF SAID STACK AND DEFINING AN ANNULAR ORIFICE SURROUNDING THE SAME, MEANS TO SUPPLY AIR UNDER PRESSURE TO SAID ANNULAR ORIFICE, SAID ANNULUS BEING ORIENTED WITH RESPECT TO SAID STACK TO PROVIDE AN ANNULAR ORIFICE HAVING AN AREA OF GREATER WIDTH TO THE REAR OF SAID STACK SO THAT THE VOLUME OF AIR TO THE REAR OF SAID STACK IS GREATER THAN THE VOLUME OF AIR FORWARD OF SAID STACK WHEREBY THE PORTION OF THE AIR COLUMN ESTABLISHED TO THE REAR OF SAID STACK WILL BE 